How do these connectors fit to modern sacs? I have launch pad fat sacs. Have previously used a tsunami pump on the twist/click connectors on the sacs. This pump obviously doesn't fit that connector (unless I'm wrong?) and the only other holes in the sac come from a small black screw cap, which when unscrewed there is just an open hole into the sac, ie no valves etc.

You do not want to use that connector on a plumbed bag. That connector is for the crappy water bed style connectors (the cheap bags). There is no seal to keep water coming out of the screw that connects to the bag, so it is only good for holding the connection when you are filling a bag topside. it will not fit fly high bags without some weird adaptors, and it will still suck. throw it away and get the proper connectors and proper bags.

Well I have a proper connector and proper bags already. I have launch pad sacks and a tsunami pump, I used these with my old boat and was fine, no leaks etc. I still have the tsunami pump but it works via a cigarette lighter, this pump is plumbed in under the rear seat of my current boat with a switch on the dash. Am I better just completely ignoring this plumbed in pump then and going back to the cigarette lighter or is there a connector I can buy for this that will get it working with the twist/lock connectors on the sacs? (And my sacs aren't plumbed anyway).

That looks like a 3/4 adapter. I think all you would need to do is get rid of the white adapter with the blue plug and get a convertor to up it to a 1". Give me a minute. I am trying to put together an adapter list.